Adaptive Droop Control of VSC-MTDC System Based on Virtual Inertia

In order to solve the problem that voltage source converter based multi-terminal direct current (VSC-MTDC) system cannot provide inertia and participate in frequency modulation after connecting AC power grid under traditional control strategy, an adaptive strategy on virtual is proposed. First, relationship between DC was established by a control, allowing VSC-MTDC side. Second, address limited coefficient selection due deviation, adopted. When deviation small, increased obtain better inertial response; contrary, reduced prevent from exceeding limit. Finally, of insufficient flexibility fixed droop coefficient, this paper introduces margin VSC-station into dynamically adjust distribution ratio unbalanced reduce deviation. The three-terminal modelled PSCAD/EMTDC simulation platform, superiority highlighted comparing it with conventional coefficient.